Aftershocks following the 2011 Tohoku-Oki earthquake driven by both stress transfer and afterslip

Abstract Aftershocks are a fundamental characteristic of seismicity, and their generation mechanism is mainly characterized by two physical models, stress transfer from large earthquakes afterslip-induced loading. However, the contribution each to aftershock remains unclear. Here we investigate spatiotemporal variations in activity following 2011 Tohoku-Oki earthquake applying Hierarchical Space–Time Epidemic-Type Aftershock Sequence (HIST-ETAS) model decade recorded seismicity since mainshock. Using estimated HIST-ETAS model, categorize aftershocks into background (which caused aseismic phenomena) triggered earthquake-to-earthquake interactions). Most that occurred updip coseismic slip zone along Japan Trench earthquakes, consistent with lack afterslip this area. Conversely, predominant type long-term downdip zone, they positively correlate evolution. Our results suggest importance combining these end-member models explain thus provide new insights relationship between distribution. classifications may also contribute monitoring given region hosts earthquake, particularly where geodetic observation networks too sparse evaluate